a butterfly valve is a quarter-turn valve
A Butterfly Valve is a quarter-turn rotational motion valve, that is used to
stop, regulate, and start flow. Butterfly valves are easy and fast to open. A
90° rotation of the handle provides a complete closure or opening of the valve.
Large Butterfly valves are usually equipped with a so-called gearbox, where the
handwheel by gears is connected to the stem. This simplifies the operation of
the valve, but at the expense of speed.
Advantages of Butterfly Valve
Compact design requires considerably less space, compared to other
valves
Light in weight
Quick operation requires less time to open or
close
Available in very large sizes
Low-pressure drop and high-pressure
recovery
Disadvantages of butterfly valves
Throttling service is limited
to low differential pressure
Cavitation and choked flow are two potential
concerns
Disc movement is unguided and affected by flow turbulence
